The Rubik's Cube was very popular when I was a kid and that means I seemed to get one every Christmas for a few years. Mostly they were given by relative who I suspect hated me. The Rubik's Cube was the single most frustrating gift I ever received, and that counts the 1400 piece puzzle printed on both sides I had.
A new charger concept called the Magic Charger has turned up that uses a cube design and has symbols you try and match, just like the Rubik's Cube. The big downside I see here is that the Magic Charger doesn't use stickers like the old Rubik's Cube did. That means you can’t cheat and peel the stickers off.
The concept uses all the motion generated by turning the different sections of the device to generate power. Exactly how much energy it could generate is unknown, it is a concept after all. You can pull the top layer of blocks up to reveal a USB port for charging devices.